hello uncle wong,could u tell me the logic used to obtain those 2 numbers ? i would really appreciate it. thanx. i sincerely believe that it may be possible to crack this sudoku without resulting in guesswork. its just that i am not an expert, therefore am not acquainted with the advanced techniques.

1. List out the possible numbers for each empty cell.(46)(46)7195382(1469)(24569)3(2678)(28)(678)(1459)(15679)(14567)(169)8(1259)(2367)4(367)(159)(15679)(1567)2(4579)(1589)(45678)(158)(146789)(145)(1567)3(1479)(4579)6(2457)3(1479)8(1257)(1457)(13478)(3457)(158)(245678)(1258)(14678)(1245)(12567)9(3789)(2379)(289)(358)6(138)(1259)4(15)(3689)(2369)(289)(3458)(158)(1348)7(1259)(15)514972638

2. See if there are any empty cell that get only one possible number.3. If the answer is yes, fill the cell with this number.4. If the answer is no (for this case, the answer is no),try to fill in a empty cell with a possible number (by guess, but still need to be inside the scope of the possibel numbers in the above list).Select the empty cell that when you fill in the number,many other empty cells will be effected.That are the two numbers that I suggested.5. List out the possible numbers for each empty cell again.6. Repeat the above steps again and again.If you get the right answer, that is fine.But if you cannot get the right answer, that means the guess workin step 4 is wrong. You have to redo the works starting at this point.

It is in fact not exactly a guess work.You have to try out each possible numbers one by one.When you reach the dead end, you have to try the next one until you solve the case.

BTW, there may be more than one answer sometimes.

I just gave this method out to another subject. Hope that it will help.

hi uncle wong,this is best that i could eliminate. after that i was stuck and then needed help. even i could have solved this su do ku with trial and error of course, however i was just wondering if it was possible to do it with pure logic and nothing else. however i do appreciate all the help you have given me. thanx a lot.

no harm done superg. i liked ur solution for the simple reason that it just goes to show that just one number here and there can do wonders to alter the solution. anyway thanx a lot for the efforts. so tso are u also of the opinion that this puzzle cannot be solved without resolving to trial and error ???